This invention relates to method and apparatus for automatically labelling containers, and more particularly to such method and apparatus for automatically applying labels to containers having a generally circular cylindrical body such that the containers can be rolled along a channel.
Labelling of containers particularly of the molded plastic variety having a generally circular cross-section is time-consuming and costly. Many labels in use today are supplied with pressure-sensitive adhesives which deteriorate with time and accordingly lose their adhesive qualities. In other words, the pressure-sensitive labels have a "limited shelf life". Such pressure-sensitive adhesive labels also cause problems in storing, are expensive and normally require a throw-away peelable backing strip for transporting and protecting the pressure-sensitive adhesive on the labels before use. When applying such labels, the backing strip must be removed before the label is mounted on the container, which is both time-consuming and a waste of the backing material and labor.
Another method employed in labelling cylindrical containers having circular cross-sections involves slightly stretching and slipping a pre-formed tubular label over the cylinder to be held thereon frictionally by being stretched around the cylinder. This type of labelling requires a difficult and time consuming manual operation as well as requiring pre-formed tubular labels of the proper critical size. If the tubular label is slightly too large, it is loose and slack and useless. If it is slightly too small, the exertion involved in stretching it around the container usually results in tearing or rupture of the label.